Method of forming cams



A. A. MEYER HE'I 'HOD OF FORMING CAMS 2 Sheets-sheaf. 1

Oct. 14, 195

Filed July 25. 1956 .A. A. MEYER METHOD OF FORMING CAMS Oct. 14, 1958Filed July 25. 1956 2 Sheets-Sheet 2 nf/I 71 I!!! m a m .q H

United States Patent O METHOD OF FORMING CAMS Arthur A. Meyer, Beloit,Wis., assignor to Warner Electric Brake & Clutch Company, South Beloit,111., a corporation of Illinois This invention relates to the art offorming a cam having an elongated surface with rises and falls thereinfor converting one motion into a thrust in a perpendicular direction.Heretofcre such cams have been formed in a so-called profiling operationby causing the metal removing cutter to follow the contour of a masterpattern.

The primary object of the present invention is to reduce the cost offorming such cams by enabling the contour of the cam surface to bedetermined by working the metal of a blank in a stamping operation.

A more detailed object is to deform the blank to a contour which is thereverse of that desired in the final cam, and, after machining of thecontoured face to produce a surface thereon of the same contour as theoriginal blank, again deforming the blank reversely to restore itsoriginal contour and thereby convert the machined surface to the desiredcontour.

The invention also resides in the novel manner of performing thematerial removing operation to permit the desired cam contour to beproduced by a subsequent flattening of the blank.

Other objects and advantages of the invention will 7 become apparentfrom the following detailed description taken in connection with theaccompanying drawings, in which Figure 1 is a perspective view of ablank from which the cam is to be formed.

Fig. 2 is a perspective view of the Fig. 1 blank follow ing the firststep in the forming operation.

Fig. 3 is a fragmentary sectional view of the die set up for performingthe deforming step.

Fig. 4 is a perspective View of the deformed blank after machiningthereof.

Fig. 5 is a diametrical sectional view of the machined blank taken alongthe line 5-5 of Fig. 4.

Fig. 6 is a sectional development view of the deformed blank taken alongthe circle 66 in Fig. 2.

Fig. 7 is a similar development view of the blank after machiningthereof.

Fig. 8 is a similar view of the completed cam.

Fig. 9 is a sectional view of the die set up for restoring the originalflatness of the blank.

Fig. 10 is a perspective view of a finished cam.

In the drawings, the invention is illustrated in connection with theformation of an axial face cam (Fig. 10) comprising a generally flatring 10 having a fiat back surface 11 and a cam track 12 extendingpartially across the opposite face and formed with alternate rises andfalls merging at high and low points 13 and 14. Preferably, though notnecessarily, the machined surface is the bottom of an annular groove 15(Fig. 9) cut in the face of the blank between the inner and outerperipheral edges thereof so as to leave flat and unmachined surfaces 16and 17 around the inner and outer margins of the ring. The latter iscomposed of ductile metal such as steel and is sufiiciently thin, forexample A of an inch, to permit working of the metal to the desiredcontour in a stamping operation. To permit the cam 2,855,667 PatentedOct. 14, 1958 ring to be coupled to a supporting shaft, spline teeth 18are formed around the inner periphery.

The first step of the improved method involves deforming the blank 10 tothe shape shown in Figs. 2 and 6. This is accomplished by compressingthe flat ring as shown in Fig. 3 between two die members 19 whoseopposed surfaces are contoured to depress angularly spaced portions ofthe blank axially and produce a contour which is the reverse of thatdesired in the final cam track 12. That is to say, the face of the blankwhich is to provide the final cam surface is formed with high and lowpoints 20 and 21 angularly spaced apart to correspond to the spacing ofthe low and high points 14 and 13 in the final cam. The back side of theblank is oppositely contoured with low points 22 alined with the lowpoints 14 of the final cam surface.

In the second step of the improved process, metal is removed along thefull length of the blank and across part of the radial width of thelatter by a simple machining operation such as milling or turning toproduce a machined surface 23 whose contour is the same as that of theoriginal blank. Where, as in the present instance, a flat blank (Fig. 1)is used at the start, metal is removed from the deformed blank (Fig. 2)down to a plane 24 (Fig. 6) thus cutting off the high points 20 aroundthe deformed surface. Such machining results in the formation of agroove of varying depth and width as shown in Figs. 4 and 5. Since metalis removed from a band of narrow width around the face of the deformedblank, the deformed contour of the inner and outer portions 25 and 26 isthus retained.

To convert the flat bottomed groove into a cam track of the desiredcontour, it is only necessary to restore the ring 10 to its originalcontour or flatness in this instance. This is accomplished simply bycompressing the deformed ring between two fiat plates 27 (Fig. 9) oneengaging the unmachined back face of the blank while the other engagesthe unmachined portions 25 and 26 on opposite sides of the groove 23. Inthis operation of flattening the unmachined surfaces of the blank, themachined surface is converted into the desired contour as shown in Figs.9 and 10. That is to say, the portions of the groove bottom adjacent thehigh points 20 of the deformed blank are displaced axially to form thedepressions 14. At the same time, the shallow points of the groove willbe moved axially of the ring a correspondingly lesser amount and thusform the high points 13 of the cam track.

It will be apparent from the foregoing that the cam surface is formed inmetal working and removing operations which may be performed at highspeed and minimum cost. Since the metal removing operation results inthe formation of a fiat surface or groove bottom, no master cam patternis required.

I claim as my invention:

1. In a method of forming a cam surface of a desired undulating contouron one axial face of a fiat blank of ductile material, the steps ofdeforming said blank to cause said face of the blank to assume a contourwhich is the reverse of said desired contour, removing from said face alayer of material narrower in radial width than the blank to form amachined surface disposed in a plane perpendicular to the axis of theblank, and restoring the unmachined surface of said blank to itsoriginal flatness and thereby cause said machined surface to assume saiddesired contour.

2. The method of forming an axial face cam comprising the steps ofbending an annular blank to provide predetermined circumferential wavepatterns on front and rear faces of the blank, cutting an annular grooveinto said front face with the bottom of the groove disposed in a planeperpendicular to the axis of the blank While retaining said wave patternin the adjacent portion of the front face, and rebending the bent blankto restore the unmachined portions of said faces to their original formand thereby cause the bottom ofthe groove to assume a circumferentialswave contour which is the reverse of said wave pattern of said frontface.

3. In the method of forming a cam surface of a desired undulatingcontour on the front face of a fiat blank of ductile material havingfront and back faces, the steps of deforming said blank to cause saidfaces to assume a contour that is the reverse of said desired contour,removing from said front face a layer of, material narrower than theblank to form a machined surface References Cited in the file of thispatent UNITED STATES PATENTS 1,714,661 Crawford et al May 28, 19292,182,067 Bruecker Dec. 5, 1939 2,557,722 Brau'chlcr June 19, 1951

